Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 271054
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
554 AM CDT THU AUG 27 2015

.UPDATED FOR 12Z AVIATION DISCUSSION BELOW...

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT THU AUG 27 2015

SHORT TERM CONCERNS ARE SHOWER THREAT RIDING EAST THIS MORNING.
THEN DEVELOPMENT OF CLOSED CIRCULATION AND HEAVY RAIN THREAT OVER
THE SOUTHERN CWA OVERNIGHT.

SPC MESOANALYSIS HAS A NARROW BAND OF MID LEVEL FRONTOGENESEIS OVER
SOUTHERN NORTH DAKOTA THIS MORNING.  AREA OF MID CLOUDS/SHOWERS AND
THUNDER THE FARTHER SOUTH IN SOUTH DAKOTA.  MCS OVER SOUTH DAKOTA
SHOULD CONTINUE TO RIDE EAST/SOUTHEAST THIS MORNING AND GRADUALLY
DECAY.  THERE WILL BE A LOT OF CLOUDS ASSOCIATED WITH THIS FEATURE
ALONG WITH THE FRONT BAND THAT MOVES ACROSS. JET STREAK RIDING NORTH
OF THE SOUTH DAKOTA COMPLEX SHOULD DRIVE THIS MID CLOUD LAYER
/FORCING EAST DURING THE MORNING.  THE TREND OF THE HRRR AND HRRR-CR
BRING THIS AREA EAST TO THE METRO BY EARLY AFTERNOON. HAD TO INCLUDE
SOME CHANCE POPS FOR THIS THREAT. NEIGHBORHOOD POPS FROM THE HIRES
CAMS ARE JUST NOW BEGINNING PICK UP ON THIS. DONT ANTICIPATE ANY
SIGNIFICANT THUNDER THREAT UNTIL LATE THIS AFTERNOON TO THE
SOUTHWEST WHERE BETTER INSTABILITY IF FORECAST.  THAT ALL DEPENDS ON
HOW MUCH HEATING WILL OCCUR HOWEVER.  HIGH TEMPERATURE FORECAST ALSO
TRICKY...WITH THE THICKER CLOUD COVER POSSIBLE AT LEAST THROUGH THE
MORNING. MID/UPPER 70S LOOK LIKELY.

THE DETERMINISITIC MODELS ARE IN FAIR AGREEMENT WITH PLACEMENT OF
HEAVIER RAIN ACROSS SOUTHERN QUARTER OF THE STATE OVERNIGHT INTO
FRIDAY. THE ECMWF IS SLOWER WITH MOVEMENT OF THE TROUGH HOWEVER. AT
THE MOMENT HAVE ABOUT 0.80 TO 1.25 INCHES QPF FORECAST FOR THE
OVERNIGHT OVER SOUTH CENTRAL MINNESOTA.  THE HIRES CAM SOLUTIONS
WERE MOVING THE HEAVIER QPF SOUTH INTO IOWA. THE 03Z SREF WAS STILL
WAS FOCUSING HEAVIER RAIN ACROSS SOUTH CENTRAL MN SO WE WILL
CONTINUE THE HIGHER QPF THIS REGION FOR NOW.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU AUG 27 2015

THE LONG TERM PERIOD STARTS OUT ON AN ACTIVE NOTE...AND THEN
FEATURES OVERALL DRY WEATHER WITH MODERATING TEMPERATURES NEXT
WEEK.

THE NORTHERN EXTENT OF /HEAVY/ RAINFALL CONTINUES TO BE THE
PRIMARY CONCERN FOR FRIDAY...GIVEN MODELS HAVE FLUCTUATED NORTH
AND SOUTH WITH THE TRACK OF THE SURFACE LOW AND ASSOCIATED
PRECIPITATION FOR SEVERAL DAYS. THE ECMWF HAS BEEN THE FARTHEST
NORTH AND MOST PERSISTENT WITH RAIN SPREADING INTO CENTRAL
MINNESOTA ON FRIDAY MORNING...AND THE OTHER MODELS HAVE TRENDED
THAT WAY. HAVE THEREFORE MAINTAINED CATEGORICAL POPS AS FAR NORTH
AS THE INTERSTATE 94 CORRIDOR /INCLUDING THE TWIN CITIES METRO AND
EAU CLAIRE/. THE INTERSTATE 90 CORRIDOR STILL LOOKS TO BEAR THE
BRUNT OF THE HEAVY RAINFALL...WHERE ONE TO THREE INCH AMOUNTS
APPEAR POSSIBLE AS PWATS INCREASE TO CLIMATOLOGICAL MAXIMUMS /1.75
INCHES/ AND COMBINE WITH A HEALTHY LLVL JET OF 45KTS.

THE ECMWF SOLUTION ALSO LINGERS PRECIPITATION WELL INTO FRIDAY
AFTERNOON ALONG AND EAST OF THE INTERSTATE 35 CORRIDOR...GIVEN IT
IS MUCH STRONGER AND SLOWER WITH THE LOW. LEANED TOWARD A SLIGHTLY MORE
OPTIMISTIC SCENARIO CLOSER TO WHAT THE 27.00Z GFS
INDICATES...BUT IT STILL LOOKS LIKE A SOGGY DAY FROM SOUTH/EAST
CENTRAL MN INTO CENTRAL WI. FRIDAY HIGH TEMPERATURES WILL BE
IMPACTED NOTABLY WITH THE ANTICIPATED CLOUDS/PRECIP...WITH MID 60S
/SOUTHEAST/ TO MID 70S /NORTHWEST/ EXPECTED.

REGARDLESS OF WHAT MODEL IS SELECTED...WE SHOULD CLEAR OUT FOR
SATURDAY...WITH LIGHT WINDS AND MILD TEMPS IN THE MID 70S TO LOWER
80S.

THE REMAINDER OF THE LONG TERM FORECAST IS MARKED BY MODERATING
TEMPERATURES AS LLVL TEMPS GRADUALLY RISE. SHOULD SEE MID/UPPER
80S FOR MOST OF THE UPCOMING WEEK. A WASHED OUT FRONT WILL HANG
OUT NEAR THE AREA MID TO LATE NEXT WEEK...BUT TEMPS ALOFT ARE
LIKELY TOO WARM FOR CONVECTIVE DEVELOPMENT GIVEN THE LACK OF
FORCING. HAVE THEREFORE KEPT THE FORECAST MOSTLY DRY FOR NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 555 AM CDT THU AUG 27 2015

LOW CONFIDENCE ON OVERALL TRENDS IN TIMING OF -SHRA INTO THE DAY.
SOME CHANCE OF ACTIVITY MOVING EAST/SOUTHEAST ACROSS MN PORTION
OF THE FA DURING THE MORNING PER TREND OF THE RAP/HRRR. SHOULD
REMAIN VFR WITH SLOWLY LOWERING MID CLOUD DECK TO MVFR INTO THE
EVENING OUT WEST...SPREADING EAST AFTER 06Z. IT SHOULD REMAIN VFR
INTO MOST OF WEST CENTRAL WI INTO TONIGHT. MORE WIDESPREAD RAIN
WITH ISOLD THUNDER POSSIBLE DEVELOPING SOUTHWEST THIS EVENING AND
ACROSS SOUTHERN MN INTO FRIDAY MORNING. SHOULD SEE IT MOVE INTO
WISCONSIN MAINLY AFTER 06Z. BEST THUNDER THREAT AROUND KRWF LATE
AFTERNOON/EVENING. LOWER IFR CIGS LIKELY DEVELOPING AFTER 08Z
INTO THE SOUTHWEST TOWARD EASTERN MN AFTER 12Z FRI.

KMSP...
VFR CONDITIONS EXPECTED THROUGH AT LEAST 06Z FRI. WILL SEE A
CHANCE OF -SHRA MOVING INTO THE AREA AFTER 18Z BUT IT SHOULD
REMAIN LIGHT AND WEAKEN AS IT MOVES INTO THE AREA. THEN MORE
WIDESPREAD -SHRA/RA BR EXPECTED WITH MVFR CIGS DEVELOPING AFTER
09Z LATE. SOME THREAT OF THUNDER...BUT BELIEVE THAT WILL BE
LIMITED TO SOUTHWEST MN AT THIS TIME. LIGHT SOUTHEAST WIND INTO
THE NIGHT GENERALLY 10KTS OR LESS.

/OUTLOOK FOR KMSP/
FRI AFTN...VFR. CHC MVFR SHRA. WINDS SE 7-15 KTS.
SAT...VFR. WINDS SE 5-10 KTS.
SUN...VFR. WINDS S 5-10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...DWE


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